Adds driver type/name to SQS transport
Fix for retry_over_time when no errback specified
Updates Changelog
Bumps version to 2.5.9
tests passing
Set release-date for 2.5.9
URL parsing: do not eat to much after the +.  Fixes celery/celery#103
Adds kombu.disable_insecure_serializers / enable_insecure_serializers
Merge branch '2.5'

Conflicts:
	README.rst
	kombu/__init__.py
Disable pickle/yaml/msgpack by default